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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9dcaeeb8ca5cfb3efdb7e022e4f007e3f61c1ba05f46f907b1ccbbccb0906c1' 
  AND token = 'meXsu2u1qr7WAhbXcJErbq1r0siQd6p04ioEHLELKRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}